No. 50.] 
365 
Mohawk river, where in no place is it 30 feet in thickness. Its layers, 
like most of the New-York rocks, are generally divided by cracks or 
fissures, having a two-fold direction, presenting a double system of 
parallel lines of separation. Though the cracks are not always con- 
tinuous, owing to unequal resistance in the rock, yet their direction 
nevertheless is uniform, and to speak approximately, for the sake of a 
convenient expression, their direction is north and south for one sys- 
tem, and east and west lor the other system. 
High expectations were at one time entertained, that this rock would 
prove to be a metalliferous one from the abundance of small particles 
of lead ore, visible near Martinsburg, about half a mile northwest of the 
village. The working for ore was commenced at the upper part of the 
limestone, which there has but a thin covering of earth or soil. The 
rock shows the two-lold system of cracks or joints, more or less regu- 
lar as to direction and irregular as to width. These cracks or joints, 
are filled with white sparry limestone, containing ores of lead, zinc and 
pyrites, forming as many veins in the space uncovered, as there are 
east and west joints or cracks. The veins are not always continuous, 
either downwards or in a horizontal direction, from the cause before 
mentioned, so that they are often interrupted, and a rock without seam 
or any indication of one must be passed to recover the part lost. In 
width, the veins vary from walls almost in contact with each other, to 
walls eight or more inches distant from each other. Sometimes the 
vein divides in consequence of two cracks or joints coming together, 
or conversely, two joints meeting in one. 
There are several parallel workings, all " open to the day," one of 
which extends for 200 feet along the surface, and in one place is 50 
feet deep. The ore is galena, accompanied by blende, and copper, 
and iron pyrites, having a matrix of white laminar and granular carbo- 
nate of lime. There is an appearance of calamine in some of the ore, 
in which the galena presents a beautiful feathery form of crystalliza- 
tion. 
The workings are now suspended. About §3,000 have been ex- 
pended upon them, and the quantity of metallic lead obtained was but 
small for the ore obtained, and for the money expended, owing, as I 
am informed, to the quantity of rock excavated for the ore gotten out, 
and for want of a proper system of drainage, &c. That there is lead 
ore in that locality is certain, from the numerous cracks or veins which 
